The goal of the proposed research is to understand the behavioral and physiological functioning of the senses of smell and taste. To approach an understanding of olfaction and gustation we shall use a mammalian species, the laboratory mouse (Mus musculus), that is amenable to behavioral, genetic, and physiological experimentation. The overall plan involves two phases. In the first a screening procedure is employed to identify inbred strains of mice that are genetically aberrant in response to specific chemical stimuli. The second phase is to identify the precise nature and causes of the genetic variants in chemosensitivity through application of the methods of animal psychophysics, behavior genetics, and sensory electrophysiology.